Diego Rodriguez, 20, of Norwood Park, sexually assaulted his ex-girlfriend and then dragged a cop with his car as the officer tried to intervene, prosecutors said. View Full Caption

Chicago Police Department

COOK COUNTY CRIMINAL COURTHOUSE — An off-duty University of Illinois at Chicago police officer was dragged by the driver of a car when she tried to rescue a woman who was being held captive in the car, prosecutors said.

Diego Rodriguez, a 20-year-old Norwood Park man, was charged with aggravated battery of a police officer and sexual assault after prosecutors said he raped and choked his 19-year-old ex-girlfriend a week after she broke it off with him, and then injured the police officer who stepped in to save her.

Rodriguez met his ex on Saturday night, after she was finished working, prosecutors said. The woman fell asleep as Rodriguez drove her car and woke up to him assaulting her, prosecutors said.

The man then choked the woman, causing her to lose consciousness, prosecutors said.

He drove to an alley behind his house in the 6300 block of West Raven Street early Sunday morning, grabbed a scissors and stuck a piece of tape over the woman's mouth, prosecutors said.

When the ex-girlfriend saw the UIC officer from the car where Rodriguez, 20, was holding her captive, she ripped the tape from her mouth and started screaming, prosecutors said.

The officer, a 28-year-old woman, ran to help, identifying herself as a police officer, prosecutors said. But Rodriguez pulled his victim back into the car and stabbed her in the torso with the scissors, prosecutors said..

The officer grabbed the woman in an attempt to pull her from the car, prosecutors said, but Rodriguez drove away, dragging the officer. She lost her grip and fell to the pavement, and the girlfriend rolled out of the car when Rodriguez turned a short distance down the road.

The ex-girlfriend suffered puncture wounds in her torso, a bite mark on her elbow, cuts on her feet and soreness around her neck, prosecutors said.

The officer had cuts around her left eye and on her chest, thighs and knees.